The use of scented or essential oils as perfumes in a wide variety of products to impart a desired odor to the products is very common. However, the use of certain scented oils in some products is precluded due to incompatability between the scented oils and the products. In particular, many scented oils are susceptible to degradation due to oxidation. Therefore, it can be difficult to impart desired odor characteristics to products having oxidizing properties due to the presence of oxidative constituents. One class of products that is particularly difficult to impart desired odor characteristics to because of their oxidative constituents are products containing dry bleaches.
Consumer objection to unpleasant product odors can often be substantially reduced by providing a pleasant odor in the headspace of the product container to mask an unpleasant product odor. One potential method for imparting desired odor characteristics to the headspace of the container of such products is to impart the desired odor to the container rather than to the product. Such a method is disclosed in European Patent Application Publication No. 0,004,463 A2 published on Oct. 3, 1979, where perfume is sprayed on an absorbent material, such as the product carton itself, from which it diffuses into the headspace of the carton. A similar method is disclosed in U.S. Pat. No. 3,711,024 issued to Hammond on Jan. 16, 1973, for imparting a desired odor to the product contained in the carton (in this case tissues).
The present invention involves forming an adhesive aqueous emulsion of scented oils, polymer, and water which upon drying entraps a high level of scented oils in a polymer matrix. The polymer matrix with entrapped scented oils can be included in a product container where the scented oils slowly diffuse from the polymer matrix over an extended period of time to provide the desired odor characteristics in the product container, particularly in the headspace. The scented oils entrapped within the polymer matrix are protected from the product so that oxidative degradation of the scented oils does not occur.
Perfumes have been incorporated in adhesive polymeric substances; the most common purpose is to mask the odor of the adhesive. Examples of references which disclose such perfumed adhesives include U.S. Pat. Nos. 2,397,817 issued to Staunton, Close and Hess on Apr. 2, 1946; 2,963,454 issued to Drugge and Hine on Dec. 6, 1960; 3,919,138 issued to Keegan, Patel and Rubin on Nov. 11, 1975; 4,160,750 issued to Columbus and Anderson on July 10, 1979; and 4,170,585 issued to Motegi and Kimura on Oct. 9, 1979; British Patent application No. 2,085,463 issued on Apr. 28, 1982; and Japanese Pat. Nos. 99,731 issued on Sept. 20, 1974, 46,911 issued on Nov. 27, 1972, 58,591 issued on May 26, 1978, and 123,442 issued on Oct. 27, 1978.
Molded polymeric objects having relatively high levels of perfume entrapped within the polymers are disclosed in the following references: U.S. Pat. Nos. 3,505,432 issued to Neuwald on Apr. 7, 1970; 3,553,296 issued to Gaeckel on Jan. 5, 1971; 4,051,159 issued to Tsoucalas, Barclay and Rogers on Sept. 27, 1977; 4,095,031 issued to Engle on June 13, 1978; 4,110,261 issued to Newland on Aug. 29, 1978; 4,184,099 issued to Lindauer, Munteanu, Reich, and Pelliza on Jan. 15, 1980; and 4,257,176 issued to Hartung and Siegel on Mar. 24, 1981; and Japanese Pat. No. 20,055 issued on Feb. 25, 1981.
Thin layers or films of polymeric materials containing scented oils are disclosed in U.S. Pat. Nos. 3,655,129 issued to Seiner on Apr. 11, 1972; 3,685,734 issued to Paciorek and Norton on Aug. 22, 1972; and 3,939,099 issued to Tusa and Tranner on Feb. 17, 1976. Seiner discloses the making of a scented polymeric film by dispersing small particles of polymer with cells of scented oils within the polymer in an aqueous emulsion and then spreading the emulsion on a surface to dry thereby forming such film. Tusa and Tranner discloses an alcohol-water solution containing polymer and perfume which is applied to human skin to achieve odor release over an extended time period.
U.S. Pat. No. 3,565,831 issued to Detert on Feb. 23, 1971, discloses a Christmas tree spray containing perfume, alcohol solvent, cellulose ether, and rosin which is used to impart a pine odor to artificial Christmas trees.
U.S. Pat. No. 3,688,985 issued to Engle on Sept. 5, 1972, discloses the impregnation of fragrance in molded plastic objects by contact with an aqueous emulsion containing about 10% scented oil. The emulsion may contain polyvinyl alcohol as a protective colloid. British Pat. No. 12,610 issued on Oct. 4, 1886, discloses solid perfume products made by the addition of at least 25% scented oils to a water-based paste of certain mineral salts.
U.S. Pat. No. 3,775,227 issued to Wilber and Brown on Nov. 27, 1973, discloses formulations in which up to 45% essential oils are mixed with aqueous-based polymer emulsions containing finely divided absorbent particles. Such mixtures are used to coat molded plastic objects in order to provide them with a long lasting odor. The emulsions are prepared at relatively low temperatures to prevent thermal degradation of the fragrant oils.